Subtask C requires the classifier to identify three types of offense target, 'Individual' ('IND'), 'Group'('GRP') and 'Other'('OTH'). The training set is rather imbalanced: The minority class OTH constitutes around 10 percent of all the instances, and only occurs once in the trial data.
We originally were planning to use the same approach as for subtasks A. However, experiments on the trial data showed a weak performance.
For this reason, we decided to use a linear SVM classifier to identify the offense target with three sub-classes since previous studies indicate that SVM classifiers perform well on classification tasks and at par with deep neural networks when features are well selected [1]}, [2]}. For this classifier, we used the Scikit-learn [3]} implementation, and we used only the training data provided by the shared task.
